The present invention relates generally to navigation aids. More particularly, it concerns a viewing device which allows one to superimpose a Global Positioning System (GPS) location onto a transparent map image.
The prior art teaches devices which use map transparencies mounted in a frame with a lens and a rotatable grid to facilitate map bearing. Such a device is shown, for example, in U.S. Pat. No. 3,094,781 to Vangor and U.S. Pat. Nos. 5,060,390 and 5,339,528 to Hill. However, these devices do not integrate the actual position of the viewer based on GPS data, with map information to help eliminate navigation error for amateur navigators.